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Decision process regarding nuclear generation: the brazilian case
Get PDFCountries face a constant need to expand their electricity generation capacities. Electricity sources in a country
and the respective generation technologies have different technical, economic, environmental, social and
political characteristics. The evaluation criteria of the generating sources and their technologies must not be
restricted to the supply of the increased demand at the lowest cost. Compliance with other public policies must
be considered in the decision process of the expansion, for instance, maximize local acquisition and minimize
foreign fuel purchase. Countries have different energy resources, as well as different levels of technology and
development in their industrial parks. Brazil has many mineral reserves, besides the hydraulic potential, for
supporting the expansion. The decision process in this sector, which includes nuclear energy as a sub-sector,
requires analyzing and evaluating various information and data. In this stage, a quantitative model providing a
first approach for the decision may be applied. The new institutional structure adopted in the sector during the
1990s and 2000s brought about new conditions into an already complex decision process. In such context of
methodology complexity, political aspects gain relevance, becoming of increased importance. The political
environment is described and the players are identified. One conclusion and a few recommendations are
provided
Desenvolvimento de algoritmos paralelos baseados em GPU para solução de problemas na área nuclear
No full textUnidades de processamento gráfico ou GPUs, são co-processadores de alto desempenho destinados inicialmente a melhorar ou prover de capacidade gráfica um computador. Desde que pesquisadores e profissionais perceberam o potencial da utilização de GPU para fins gerais, a sua aplicação tem sido expandida a outras áreas fora do âmbito da computação gráfica. O principal objetivo deste trabalho é avaliar o impacto de utilização de GPU em dois problemas típicos da área nuclear. O transporte de nêutros utilizando simulação Monte Carlo e a resolução da equação do calor em um domínio bi-dimensional pelo método de diferenças finitas foram os problemas escolhidos. Para conseguir isso, desenvolvemos algorítmos paralelos para GPU e CPU nos dois problemas descritos anteriormente. A comparação demonstrou que a abordagem baseada em GPU é mais rápida do que a CPU em um computador com dois processadores quad core, sem perda de precisão nos resultados encontradosGraphics Processing Units (GPU) are high performance co-processors intended, originally, to improve the use and quality of computer graphics applications. Since researchers and practitioners realized the potential of using GPU in two tipical problems of Nuclear area. The neutron transport simulation using Monte Carlo method and solve heat equation in a bi-dimensional domain by finite differences method. To achieve this, we develop parallel algorithms for GPU and CPU in the two problems described above. The comparison showed that the GPU-based approach is faster than CPU in a computer with two quad core processors, without precision loss
Avaliação acustoelástica do aço 20 MnMoNi 55, material estrutural do vaso de pressão dos reatores nucleares de Angra II e III
No full textOs vasos de pressão das usinas nucleares Angra II e III, que são de grandes espessuras, têm como um
dos seus componentes estruturais o aço 20 MnMoNi 55. A avaliação acustoelástica realizada através de
ensaios ultrassônicos foi baseada na variação de velocidade da onda ultrassônica cisalhante de
incidência normal em função da tensão aplicada no material, utilizando-se a técnica de birrefringência
acústica, que é fundamentada na diferença fracional da velocidade da onda ultrassônica em relação à
duas direções perpendiculares. Neste trabalho foram realizadas duas experiências. Na primeira, foi
avaliado para esta técnica de análise de tensão um novo método de aquisição de sinais ultrassônicos
que foi comparado com o método usual, pretendendo determinar suas potencialidades e limites para a
aplicação em materiais com até 120 mm de espessura. Na segunda, foi realizado o estudo do
comportamento acustoelástico do aço 20 MnMoNi 55. O novo método de aquisição de sinais
ultrassônicos apresentou resultados satisfatórios e foi utilizado no estudo acustoelástico do aço 20
MnMoNi 55. A análise acustoelástica indicou que o material apresenta uma comportamento anisotrópico
e heterogêneo. A constante acustoelástica do material, obtida experimentalmente através de ensaios de
compressão realizados em corpos-de-prova do aço 20 MnMoNi 55, foi utilizada para a análise de tensão
de forma quantitativa. Um corpo-de-prova do aço 20 MnMoNi 55 foi submetido à um ensaio de flexão
para realizar a análise de tensão de forma qualitativa através da diferença entre as birrefringências
obtidas durante o carregamento (B) e antes do carregamento (B0), em cada ponto estudado. Com os
resultados obtidos foi possível identificar qualitativamente e quantitativamente as regiões compressivas e
trativas. A realização destes ensaios permitiu verificar a eficiência da técnica ultrassônica de
birrefringência acústica para analisar o estado de tensões.The pressure vessels of the Angra II and Angra III nuclear power plants, which are of large thickness,
have as one of their structural components the 20 MnMoNi 55 steel. The acoustoelastic evaluation carried
out through non-destructive ultrasonic tests was based on the variation of the speed of ultrasonic shear
waves of normal incidence as a function of the stress applied in the material using the acoustic
birefringence technique, which considers the fractional difference of the speeds of two ultrasonic waves
propagating in orthogonal directions. In this work two experiments were carried out. In the first one, a new
method for acquisition of ultrasonic signals for joint application with this technique of stress analysis was
evaluated by comparison with the conventional one. The aim was to determine its potential and limitations
for application in materials up to 120 mm of thickness. In the second experiment, the acoustoelastic
behavior of the 20 MnMoNi 55 steel was studied. The new method of acquiring ultrasonic signals led to
satisfactory results and was used in the study of the acoustoelastic behavior of the 20 MnMoNi 55 steel.
The acoustoelastic analysis indicated that the material has an anisotropic and heterogeneous behavior.
The acoustoelastic constant of this material, obtained experimentally from the analysis of the graphs of
the material behavior (birefringence x stress) under compression tests performed on specimens of the 20
MnMoNi 55 steel, was used for the quantitative stress analysis. A specimen of the 20 MnMoNi 55 steel
was subjected to a bending test to carry out a qualitative stress analysis through the difference between
the values of the birefringence obtained during loading (B) and before loading (B0) in every point studied.
With the obtained results it was possible to identify qualitative and quantitatively the regions of the
specimen under compressive and tensile stresses. The execution of these tests allowed to verify the
efficiency of the ultrasonic technique of the acoustic birefringence for the analysis of stress states
Montagem do sistema para dosimetria de nêutrons com detectores de bolhas
Get PDFSão descritos a montagem e o procedimento desenvolvido para a aquisição e analise de imagens obtidas com os novos detectores de bolha BDS, para dosimetria de nêutrons ou nas medições de fluência e distribuição de energia de nêutrons de uma instalação nuclear
Managing Knowledge: a technology transfer case study in IEN
Get PDFKnowledge management is paramount nowadays. In order to enable the members of an organization to deal
with their current situations effectively it is mandatory to know and enhance its intellectual capital. Managing
the organization knowledge is important to the extent that it allows and reinforce its mission (what we are trying
to accomplish?), and performance (how do we deliver the results?). As a result of a knowledge management
effort, the organization can create value for itself and for society as a whole. In this paper, we argue that a technology developed at a research institute and transferred to an industry is knowledge to be managed in order to create value, both for the society and for the Institute. In order to manage such knowledge, it is proposed an approach to enhance the value creation potential of a technology transfer. This paper propose an investigation to expand the understanding on how a public research institute and a private firm could introduce their value creation wishes into a technology transfer agreement in a way to reflect and provide the realization of those wishes. It is proposed that, from the identification of the organizations expectations it is possible to infer which agreement attributes will contribute to that value creation and to establish satisfactory agreement configurations. These configurations have the potential to generate those consequences, given that, through the transfer, each organization seeks to increase potential benefits and to reduce potential sacrifices. Supported by exchange flow and value creation models, by the knowledge management and the means-end theory, an approach to increase the value creation potential of a technology transfer is proposed. Evidences from a case study sustain the proposed approach. The case study unity is the Instituto de Engenharia Nuclear, a public research institute
Man system interface based on automatic speech recognition: integration to a virtual control desk
Get PDFThis work reports the implementation of a man-system interface based on automatic speech recognition, and its integration to a virtual nuclear power plant control desk. The later is aimed to reproduce a real control desk
using virtual reality technology, for operator training and ergonomic evaluation purpose. An automatic speech
recognition system was developed to serve as a new interface with users, substituting computer keyboard and
mouse. They can operate this virtual control desk in front of a computer monitor or a projection screen through
spoken commands. The automatic speech recognition interface developed is based on a well-known signal
processing technique named cepstral analysis, and on artificial neural networks. The speech recognition
interface is described, along with its integration with the virtual control desk, and results are presented
A PSO approach for preventive maintenance scheduling optimization
Get PDFThis work presents a Particle Swarm Optimization (PSO) approach for preventive maintenance policy
optimization, focused in reliability and cost. The probabilistic model for reliability and cost evaluation is
developed in such a way that flexible intervals between maintenance are allowed. As PSO is skilled for realcoded continuous spaces, a non-conventional codification has been developed in order to allow PSO to solve scheduling problems (which is discrete) with variable number of maintenance interventions. In order to evaluate the proposed methodology, the High Pressure Injection System (HPIS) of a typical 4-loop PWR has been considered. Results demonstrate ability in finding optimal solutions, for which expert knowledge had to be
automatically discovered by PSO
Uma metodologia baseada em algoritmo de otimização por enxame de partículas para manutenção preventiva focada em confiabilidade e custo
No full textNeste trabalho, um algoritmo de Otimização por Enxame de Partículas (PSO, do inglês
“Particle Swarm Optimization”) é desenvolvido para aplicação na otimização de políticas
de manutenção preventiva. A metodologia proposta que permite intervalos flexíveis entre
manutenções, ao invés de considerar os períodos fixos, possibilita uma melhor adaptação
dos agendamentos, a fim de lidar com as taxas de falha dos componentes em
envelhecimento. Por outro lado, devido a essa flexibilidade, o planejamento de manutenção
preventiva se torna uma tarefa difícil. Motivada pelo fato do PSO ter demonstrado ser
muito competitivo em relação a outras ferramentas de otimização, este trabalho investiga a
sua utilização como uma ferramenta alternativa de otimização.
Considerando que o PSO trabalha em espaço real e contínuo, torna-se um desafio sua
aplicação a um problema de otimização discreto considerando agendamentos onde a
quantidade de intervenções pode ser variável. O PSO desenvolvido neste trabalho apresenta uma modelagem original que contorna tal dificuldade, permitindo a aplicação do mesmo ao
problema proposto.
O PSO proposto destina-se a pesquisa para a melhor política de manutenção e considera
vários aspectos relevantes, tais como: i) a probabilidade de necessitar uma reparação
(manutenção corretiva), ii) o custo de tais reparos, iii) tempos de parada típicos, iv) os
custos de manutenção preventiva, v) o impacto da manutenção na confiabilidade dos
sistemas como um todo, e vi) a probabilidade de manutenção imperfeita.
A fim de avaliar a metodologia proposta, optou-se por investigar um sistema eletromecânico
composto por três bombas e quatro válvulas, o “Sistema de Injeção à Alta
Pressão (HPIS)’ de um reator nuclear tipo PWR. Os resultados demonstram que o PSO com
a modelagem proposta é eficiente na busca ótima da manutenção preventiva para as
políticas de manutenção preventiva para o HPIS.In this work, a Particle Swarm Optimization Algorithm (PSO) is developed for
preventive maintenance optimization. The proposed methodology, which allows the use
flexible intervals between maintenance interventions, instead of considering fixed periods
(as usual), allows a better adaptation of scheduling in order to deal with the failure rates of
components under aging. Moreover, because of this flexibility, the planning of preventive
maintenance becomes a difficult task. Motivated by the fact that the PSO has proved to be
very competitive compared to other optimization tools, this work investigates the use of
PSO as an alternative tool of optimization.
Considering that PSO works in a real and continuous space, it is a challenge to use it
for discrete optimization, in which schedulings may comprise variable number of
maintenance interventions. The PSO model developed in this work overcome such
difficulty.
The proposed PSO searches for the best policy for maintaining and considers
several aspects, such as: i) probability of needing repair (corrective maintenance), ii) the cost of such repairs, iii) typical outage times, iv) costs of preventive maintenance, v) the
impact of maintaining the reliability of systems as a whole, and vi) the probability of
imperfect maintenance.
To evaluate the proposed methodology, we investigate an electro-mechanical
system consists of three pumps and four valves, "High Pressure Injection System (HPIS) of
a PWR. Results show that PSO is quite efficient in finding the optimum preventive
maintenance policies for the HPIS
Metodologia para estudos de circulação natural em circuitos fechados
No full textEste trabalho apresenta os resultados de uma análise de estabilidade do fenômeno de
circulação natural monofásica unidimensional em um circuito fechado, através de uma
simulação computacional com o método de elementos finitos. Para isso utilizaremos as
equações de Navier-Stokes em coordenadas cartesianas para os balanços de massa, momento
e uma equação de energia. Esta formulação foi implementada em um código computacional,
originalmente desenvolvido no Instituto de Engenharia Nuclear(IEN-CNEN) estando o
mesmo disponível para futuras análises e projetos de usinas nucleares.This work presents the results obtained from the analysis of stability of the phenomenon of
the natural circulation for one-dimension single-phase flow in a closed loop, by a computer
program with the method of finite element. The Navier-Stokes equations in cartesian
geometry were used for the balance of mass, momentum and one equation for energy. The
formulation has been implemented in a computer code developed at the Nuclear Engineering
Institute(IEN-CNEN) and is now available either for futures analysis or design of nuclear
systems
HUMAN FACTORS QUESTIONNAIRE AS A TOOL FOR RISK ASSESSMENT.
No full textFatores Humanos QUESTIONÁRIO COMO INSTRUMENTO DE RISCO
AVALIAÇÃO
A engenharia de fatores humanos (HFE) como uma disciplina, e como um processo, procura descobrir e aplicar
conhecimento sobre as capacidades e limitações humanas para design de equipamento e sistema, garantindo que o sistema
design, tarefas humanas e ambiente de trabalho são compatíveis com o sensorial, perceptual, cognitivo e físico
atributos do pessoal que opera sistemas e equipamentos. Significância de riscos considera a magnitude
as conseqüências (perda de vidas, danos materiais, a degradação ambiental) e a frequência de ocorrência de
um evento adverso particular. A concepção do questionário baseou-se nos seguintes definições: a pontuação ea
classificação do risco para a segurança nuclear. O principal benefício da aplicação de uma abordagem baseada no risco
importância no desenvolvimento do questionário é para garantir a identificação e avaliação das características
dos projetos, relacionados a fatores humanos, que afetam o risco para a segurança nuclear, as ações humanas e a segurança dos
os sistemas das instalações nucleares. O questionário fatores humanos desenvolvida neste estudo fornecerá informações valiosas
apoio à avaliação de risco, possibilitando a identificação de problemas de design que podem influenciar a
avaliação do risco para a segurança nuclear.The human factors engineering (HFE) as a discipline, and as a process, seeks to discover and to apply
knowledge about human capabilities and limitations to system and equipment design, ensuring that the system
design, human tasks and work environment are compatible with the sensory, perceptual, cognitive and physical
attributes of the personnel who operates systems and equipment. Risk significance considers the magnitude of
the consequences (loss of life, material damage, environmental degradation) and the frequency of occurrence of
a particular adverse event. The questionnaire design was based on the following definitions: the score and the
classification of the nuclear safety risk. The principal benefit of applying an approach based on the risk
significance in the development of the questionnaire is to ensure the identification and evaluation of the features
of the projects, related to human factors, which affect the nuclear safety risk, the human actions and the safety of
the nuclear plant systems. The human factors questionnaire developed in this study will provide valuable
support for risk assessment, making possible the identification of design problems that can influence the
evaluation of the nuclear safety risk